Over at the New York Times, John Harwood listed the economy as an asset for the Democrats in the midterm elections. I’m not so sure about that.

The unemployment rate has fallen below 6 percent and we have had six months of decent GDP growth, but we should also think about the “trend.” Post–World War II GDP looked like it had been steadily growing about 3 percent a year. In reality, it didn’t grow at a perfectly steady 3 percent. Sometimes the economy grew faster than 3 percent but fell into recession. Sometimes the economy fell into recession and the number slipped below the “trend” growth rate but, in the recovery, the economy would grow faster than 3 percent for a while and the economy would get back to trend. We made up the lost ground until it was like the recession never happened.

This time it is different. While the economy is larger than it was before the great recession, we are still way behind the “trend.” We never had the catch up growth (or at least we haven’t had it yet).

Most Americans have no idea of the trend, but they probably have a set of expectations of what the economy should be like after five years of economic growth. If we had stayed at “trend,” if we had experienced catch-up growth, the economy would be larger today. It is not at all contradictory to think that the economy is better than it was at the bottom of the recession and well short of what they expected it to be at this stage of the recovery.

This gets to the Obama problem with the economy. The best campaign speech of 2012 was Bill Clinton’s explanation of the Obama economic record. Clinton’s argument was that the Republicans had created a hole so deep that it took Obama’s masterful economic management years to dig out. It was plausible, but that argument also has a half-life. The farther we get from Bush, the less this becomes Bush’s economy. The disappointments of the populace are directed against the current president.

At this point, telling the populace that these are the good times isn’t going to help the Democrats. That will continue to be the case until we make up the lost ground, or the American people lower their expectations.